Priming apparatus for centrifugal pumps



March 17, 1936.

A. c. DURDIN, JR

PRIMING APPARATUS FOR CENTRIFUGAL PUMPS Filed Feb. ll, 1935 2 Sheets-Sheet 1 INVENTOR.

ATTORNEY.

March 17, 1936. A, c. DURDIN, JR

PRIMING APPARATUS FOR CENTRIFUGAL PUMPS Filed Feb. l1, 1935 2 Sheets-Sheet 2 INVENTOR.

W, ww M U@ .,lw Wm@ 4A 7f3 lE 0 2 ATTORNEY.

Patented Mar. 17, 1936 UNITED STATES .PATENT OFFICE Augustus C. Dui-din, Jr., Niles Center, Ill., as

signor to Chicago Pump Company, Chicago,

Ill., a corporation of Illinois Application February 11,1935, Serial No. 6,00

13 Claims.

This invention relates to priming apparatus for centrifugal pumps, and its principal object is to provide novel means for preventing water or other liquid from entering the priming pump. AnotherA object is to provide novel means for priming two or more centrifugal pumps by a single priming pump. Another object provides novel priming means in connection with duplex centrifugal pumps or a battery of centrifugal pumps, whereby the priming of any pump, While another is or others are in operation will not interfere with the operation of any of the pumps.

Another object is to provide a pumping system in which a wet vacuum or dry vacuum pump l5 may be employed for priming one or several centrifugal pumps. Another object is to provide novel means whereby the priming pump may remain idle except when necessary to prime any one of the centrifugal pumps served by it.

Other objects and advantages will appear in the course of this specification and with all of said objects and advantages in view, this invention consists in the several novel features hereinafter fully set forth and claimed.

The invention is clearly illustrated in the drawings accompanying this specication in which:

Fig. l is a diagrammatic view, in side elevation, of a centrifugal pump unit equipped with one form of the priming apparatus embodying the present invention;

Fig. 2 is a deta'l vertical section through the primer seen in Fig. 1;

Fig. 3 is a detail horizontal section taken on the line 3-3 of Fig. 2; Fig. 4 is a detail horizontal section taken on the line 4-4 of Fig. 2;

. Fig. 5 is an end elevation of a duplex pumping installation equipped with a common vacuum tank or chamber connected to the primer of each pump;

Fig. 6 is an end elevation of a duplex pumping installation equipped with a single motor driven priming pump controlled by the primer of each centrifugal pump, and

` Fig. 'Z'is a side elevation of a single centrifugal pump unit equipped with a continuously driven priming pump.

Referring to said drawings, and first to Figs. 1

to 4 inclusive, the reference character I0 designates a base having a raised pad II, upon which is mounted an electric motor I2. Mounted on the base is a centrifugal water pump I4 of conventional form, the shaft 4of which is connected to the motor shaft by a shaft coupling I5. Pedestais I3 support the pump casing in cofaxial align- (Cl. 10S-113) ment with the motor shaft. A suction inlet pipe I6 connects with` the suction inlet of the centrifugal pump I4 through a T fitting I8 Aand a discharge pipe I1 leads from thedischarge outlet of the pump, I9 designates a cap or cover for a 5 clean cut opening in the T coupling I8. A check valve is interposed in the discharge pipe as usual.

Bolted or otherwise secured to the top of the fitting I8 is a primer chamber housing 20, which provides a float chamber 2 I, in which is contained l0 a oat 22 mounted on a float rod 23, which is guided for vertical movement in a bushing 24. Above the float chamber 2l is an air chamber 44 in which is contained valves and other mechanism as will be presently described. A dia- 15 phragm or wall 25 bolted to a flange 21 on the upper end of the housing 20, separates the float chamber from the air chamber. Desirably the housing 42, which encloses the air chamber 44, and the diaphragm 25, are fastened to the hous` 20 ing 2|)A by bolts 28 and nuts 29, 43. A gasket 26 is desirably interposed between vthe flange 21 and the housing 42 and diaphragm 25 to make1 a tight joint therebetween.

An` air passage or port extends through the dia- 25 phragm 25, which affords communication between the float chamber and air chamber. The port is closed by a check valve 30, which seats upon the seat 32 of a cage 3| that is fastened in the opening in the diaphragm. Cross wires 33 secured 30 to said cage above the valve 30 serve to retain the valve in the cage.

Extending into the air chamber 44 is a suction fitting 31, desirably having a flange 38 on its outer end bolted to the side wall of the hous- 35 ing 42 by bolts 40. A gasket 39 between the side wall and flange makes a tight joint between the housing and suction ttirig. A suction pipe 4I leads from the suction fitting 31 to a suction pump or other vacuum device 52. 40

An air port is formed in the lower wall of the suction fitting 31, which affords a communication between the air chamber 44 and the interior of the suction fitting. In the port is a valve seat 36 upon which may seat an air valve 35, mounted 45 upon the upper end of the float rod 23. 'Ihe air chamber provides an air passage from the .float chamber to the suction fitting 31. vIt is to be understood that in priming the centrifugal pump, air is exhausted from the float chamber, and suc- 5o tion inlet pipe I8, thereby permitting water to rise and enter thecentrifugal pump and oat chamber. The air suction passage to the vacuum pump leads from the float chamber, past the check valve 30, through the air chamber 44, the 55 port in the valve seat 36, the suction iitting 31 and the suction pipe 4|. When the centrifugal pump has been primed, the level of the water in the oat chamber rises to a certain level therein, the oat is lifted and it seats the air valve 35 upon the seat 36 around the port in the lsuction tting, thereby permitting the check valve 30 to close. Suction, produced by the vacuum pump, is then cut oi from the air chamber and iioat chamber, but the closing of the check valve 30 prevents air from entering the float 'chamber from the air chamber.

In the upper wall of the housing 42 is a Vent port surrounded by a valve seat 41, and controlling said vent port is a vent valve 46, which is connected to and operated by the oat. Desirably the connections between the vent valve and float may comprise a valve stem 45 on which the valve 45 is mounted and a yoke 34 to which the oat rod 23 and valve stem 45 are fastened. Inasmuch as the float supports the weight of the oat rod, air valve yoke, valve stem and vent Valve, and since the iioat must unseat the vent Valve against atmospheric pressure opposing the partial vacuum in the air chamber, the water will rise a considerable distance in the float chamber` before the float will be lifted, and when this occurs, the float and parts carried thereby are lifted suddenly, thereby suddenly closing the air port 3S and opening the vent port 41, and breaking the vacuum in the air chamber. In case of any leakage around the valve 35, air only will enter the suction litting and be carried to the vacuum pump. The parts are so proportioned and arranged that it is impossible for any water to enter the suction fitting and since the air chamberis .at atmospheric pressure (when the vent valve is open) and since the pressure in the float chamber is below atmospheric pressure, there is no likelihood for water being carried on to the vacuum pump.

In Fig. l the priming pump 52 and its motor 54 are shown as comprising a priming pump unit, separate from the water pumping unit. The priming pump 52 here shown is of the dry pump type, driven from the motor `54 by a belt 53, trained around belt pulleys on the motor and pump shafts respectively. A union coupling 5l and a. check valve 5la are desirably interposed in' the suction pipe 4l.

In connection with the form of the invention illustrated in Fig. 1, it is desirable to stop the priming pump when the centrifugal pump has been primed, and to permit the priming pump to remain idle so long as the centrifugal 4pump remains primed, and to start the priming pump, when the centrifugal pump again requires priming. Automatic means have been provided for this purpose, and as shown said means comprise a float switch 50 in the wiring circuit 55 to the priming pump motor 54. A bracket 56 supports the switch on the housing 42. Buttons 48, adjustably mounted on the upper end of the valve stem 45 are placed on both sides of the switch lever 49 of the iloat switch 50, and operate the same. Upward movement of the valve stem serves to open the switch and downward movement serves to close it. Consequently when the oat moves'upward, when the centrifugal pump has been primed, the lower button raises the switch lever, opens the circuit and stops the motor 54and priming pump 52. In case air nds its way into the iioat chamber and the water in the chamber recedes sufliciently to lower the oat, the

upper button lowers the switch lever, closes the switch and again starts the .primingpurrip motor;

setting the pumpingoutiit into operation. The' j suction through thesuction pipe and exhausts air vfrom the air chamber 44, the iioat chamber 2l and the-suction inlet pipe I6, permitting the water to rise in the suction inlet pipe, prime the centrifugal pump and enter the oat chamber. When the level of the water in the float chamber rises to a predetermined place, the iioat is suddenlylifted up, and it closes the air valve and opens the vent valve, thereby cutting oi the vacuum supply and opening the air chamber to the atmosphere, whereupon the check valve Si] closes and holds the vacuum in the float chamber. Simultaneously the lower button on the valve stem raises the switch lever .69 and'opens thev switch 50 thereby opening the circuit for the priming pump motor and stopping the priming pump. In case the water in the ioat chamber recedes far enough to permit the float to drop, the vent valve 46 is closed, the air valve 3,5 opened, and the switch is closed, thereby starting the priming pump unit, and restoring the level of the water in the iioat chamber to its former level, with the vent valve open and the air valve closed.

In the modied form of the invention illustrated in Fig. 5 two centrifugal pump installations substantially similar to the one shown in Fig. 1, are illustrated. The corresponding parts of each installation and those of the form shown in Fig. 1 are indicated by similar reference characters. In this case, however, the float switch 5U is omitted from each installation, and the suction pipe 4l, from each air chamber housing 42, lead to a vacuum tank or other vacuum chamber 51. Union couplings 5l and shut olf valves 58 are shown as interposed in the suction pipes 4|. The arrangement shown in Fig. 5 is intended for situations where it is desirable to maintain a substantially constant vacuum supply on the primer of each centrifugal pump while either or both are in operation. A priming pump unit, comprising an electric motor 62 and a vacuum pump 6|, driven thereby, is employed. The vacuum pump 6l is connected to the vacuum tank or chamber 51 by pipe connections 63, having a check valve 63a therein. Desirably the vacuum tank 51 and priming pump unit are mounted on a base 60. Pedestals 59 support the vacuum tank thereon.

For maintaining a substantially constant low pressure in the vacuum tank 51, a pressure switch is connected to the tank and controls the wiring circuit 66 for the priming pump motor 62. As shown the pressure switch comprises a diaphragm 64 connected to the tank and an electric switch 65 operated thereby. A pressure gauge 61 connected to the vacuum tank indicates the pressure therein. The pressure switch is set to open and close the circuit for the priming pump motor when the pressure in the vacuum tank, reaches certain high and low points.

In this form of the invention the priming pump unit continues to build up vacuum in the vacuum tank until the predetermined high vacuum is reached and thereupon the pressure switch operates and opens the circuit to the priming 'pump motor. When the pressure in the tank rises for any reason to the high point of the pressure range, the Vacuum switch operates and closes the circuit and again starts the motor. In this way a substantially constant low pressure, within predetermined limits, is' maintained in the vacuum tank. The operation of the primers of the two centrifugal pumps is substantially the same as that ofthe primer of the preferred form. Obviously as many centrifugal pumping units may be connected to the vacuum tank as are required.

In the modified form of the invention illustrated in Fig. 6, which also illustrates a duplex pumping installation, the two pumping units and the priming pump unit are substantially of the l same construction'as those illustrated in Figs. 1 to 4 inclusive, except thatv only one priming pump unit is employed in connection with the two centrifugal pumps. In this arrangement the two suction pipes 4I are` connected to the single suction pipe 69 of the priming pump 10 by a T tting 68. The reference characters 5I designateunion couplings in the lines SI, and 58 designate shut off-valves therein. A check valve 13 desirably is interposed in the pipe 69.

The priming pump is driven by `an' electric motor 1|, beltedor otherwise connected thereto, and the wiring circuit 12 for the motor is controlled by the iioat switches 50, which are in parallel in the circuit 12.-

`In this arrangement, when either centrifugal pump I4 requires priming, its-associated iioat switch closes the circuit for the priming pump motor and starts the motor and its priming pump,

and when both centrifugal pumps are primed the float switch 50 of the last pump to be primed, opens the circuit to the priming pump motor. As a result the priming pump unit operates only when it is necessary to prime either or both centrifugal pumps. Obviously as many pumping units may be handled by the single priming unit as are required.

' In the modified installation illustrated in Fig.

7 the centrifugal pump unit is substantially the same as that illustrated in Fig. 1 except that no oat switch is used. In this case, however, the priming pump 1B is mounted on thek base I0 and is continuously driven by the centrifugal pump motor l2, as by a belt 16 trained around belt pulleys on the motor shaft and pump shaft respectively. lThe priming pump is shown as resting on a pad 15. The air chamber of the primer is connected to the priming pump by a suction pipe il as in Fig. 1 and to prevent an excessive vacuum from being built up, a relief valve 18' is interposed in the suction line, which is arranged to open to the atmosphere whenever the pressure reaches a predetermined low point. Desirably a check valve 11 is interposed in the suctionpipe between the primer and the relief valve.

In the operation of this form of the invention, suction is continuously applied to the primer, and up to the 4suction fitting 31 (see Fig. 2)

-When the valve 35 is closed, because the priming Vpump operates continuously, but the relief valve prevents an overload on the priming pump and motor, as it opens when the pressure reaches a predetermined low place.

It is to be observed that under no circumstances can water be drawn into the priming pump. This permits the use of a dry priming pump without any danger of injury thereto. However, I do not wish to limit myself to a dry priming pump as any approved form of suction pump maybe substituted therefor.

Furthermore, an air passage is provided in the primer which is capable of supplying air at atmospheric pressure to the airvalve while the vent is open and the air valve is closed without breaking the vacuum in the suction pipe. As a result thereof, in case of a leaky air valve, air at atmospheric pressure will iind'its way through the leak to the suction pipe, but it is impossible for any water to reach the suction pipe. In case of a leaky check valve, any air now between the air chamber and float chamber (when the air chamber is vented) would be from the air chamber, through the leaky check valve, to' the float chamber, and as a .consequence water cannot be drawn into the suction pipe.

It is also to be observed that when the float lifts and closes the inlet port to" the suction pipe tl, air cannot enter the suction pipe from the 'vent at the topof the air chamber or from any other place. As a consequence the vacuum in the suction line is not broken, but is constantly ready to ,serve any other centrifugal pump handled by the priming pump or other source `cating with the suction inlet of a centrifugal pump, a float in said chamber, a second chamber communicating with the float chamber through a valve controlled port, said second named chamber having a vent port, a priming pump and a suctio'n conduit leading therefrom to the sec- Y ond named chamber and having a suction inlet,

opening therefrom, and valves operated by the float, for simultaneously closing the suction inlet to the suction pipe andopening the vent port, when the float is raised, the valve for the port between the twoi chambers operating to close when the vent port is opened. ,Y

2. In priming apparatus for centrifugal pumps, the combination of a float chamber communicating with the suction inlet of a centrifugal pump, a oatin said chamberna second chamber communicating with the float chamber through a valve controlled port, said second named chamber having a ventv'port, a continuouslyrunning priming pump and a suction con- 'duit leading therefrom to the second named two chambers operatingto close when the vent port is opened.

3. -In priming apparatus for centrifugal pumps,

the combination of a iioat chamber communicating with the suction inlet Vof a centrifugal pump, a float in said chamber, a second chamber communicating with the float chamber through a valve controlled port, said second named chamber having a vent port, a priming pump and a suction conduit leading therefrom to the second named chamber and having a suction inlet, opening therefrom, valves operated by the float, for simultaneously closing the suction inlet to the suction pipe and opening the vent port, when the oat is raised, the valve for the port between the twd chambers operating to close when the vent port is opened, an electric motor for driving said priming pump, and an electric switch in the 'wiring circuit to the motor, responsive to fluctuations in the float chamber.

4. In priming apparatus for centrifugal pumps, the combination of a oat chamber communicating with the suction inlet of a centrifugal pump, a oat in said chamber, a second chamber communicating with the oat chamber through a valve controlled port, said second named chamber having a vent port, a priming pump and a suction conduit leading therefrom to the second named chamber and having a suction inlet, opening therefrom, valves operated by the iioat, for simultaneously closing the suction inlet to the suction pipe and opening the vent port, when the oat is raised, the valve for the port between the two chambers operating to close when the vent port is opened, an electric motor for driving said priming pump, and a iioat switch in the wiring circuit to the motor, operated by said oat.

5. In priming apparatus, the combination of several centrifugal pumps, each having a float chamber communicating with the suction inlet of the pump, a float in the oat chamber, a second chamber having an air vent and a vent valve therefor, said second named chamber communicating with the oat chamber through a valve controlled port which closes when the air vent is opened, a suction pipe leading from the second named chamber and having a suction inlet opening therefrom, a suction inlet valve, and operative connections between the valves and oat whereby the vent valve is opened and the suction inlet valve is closed when the oat is raised; and a single source of vacuum supply connected to all of the suction pipes.

6. In priming apparatus, the combination of several centrifugal pumps, each having a float chamber communicating with its suction inlet, a float in said float chamber, a second chamber having an air vent and a vent Valve therefor, said second named chamber communicating with the float chamber through a valve controlled port which closes when the air vent is opened, a suction pipe leading from the4 second named chamber and having a suction inlet opening therefrom, a suction inlet valve, and operative connections between the valves and float whereby the vent opens and the suction inlet closes when the oat is raised; a vacuum tank connected to the suction pipes, an electric motor operated vacuum pump connected to the vacuum tank, and a pressure switch' connected to the vacuum tank and interposed in the wiring circuit to the motor of the vacuum pump.

'7. In priming apparatus, the combination of several centrifugal pumps, each having a oat chamber communicating with its suction inlet, a float in said oat chamber, a second chamber having an air vent and a vent valve therefor, said second named chamber communicating with the float chamber through a valve controlled port which closes when the air vent is opened, a suction pipe leading from the second named chamber and having a suction inlet opening therefrom, a suction inlet valve, and operative connections between the valves and the oat whereby the vent valve opens and the suction inlet valve closes when the iioat is raised; an electric motor driven vacuum pump having pipe connections with said suction pipes, and float switches operated by said iioats, said float switches being in parallel in the wiring circuit to the motor of the vacuum pump.

8. In priming apparatus for centrifugal pumps, the combination of a oat chamber communicating with the suction inlet of a centrifugal pump, a oat in said oat chamber, a valve chamber communicating with the float chamber through a check valve controlled port, a suction tting entering said valve chamber and having an inlet port opening to the interior of the valve chamber, a suction-pipe leading from said suction fitting and connected to a source of vacuum supply, there being a vent opening tothe interior of said valve chamber, and valves connected to and operated by said oat for simultaneously closing the inlet to the suction fitting and opening the vent when the float is raised.

9. In priming apparatus for centrifugal pumps, the combina-tion of a float chamber communieating with the suction inlet of a centrifugal pump, a iioat in said oat chamber, a v,valve chamber communicating with the float chamber through a check valve controlled port, a suction fitting entering said valve chamber andnhaving an inlet port opening to the interior of the valve chamber, a suction pipe leading from said suction fitting and connected to a source of vacuum supply, there being a vent opening to the interior of said valve chamber, valves controlling the inlet to the suction fitting and the vent, a oat rod connecting the float with one of said valves. a

opened when the float rises, and there being a` port between said chambers closed by Ea check valve, a suction fitting spaced above the bottom of the second named chamber and having a suction inlet port opening to said second named chamber, a suction pipe leading from said suction fitting to a source of vacuum supply, and a 'valve operated by the float for closing the suction inlet port to the suction fitting when the oat is lifted.

11. In priming apparatusy for centrifugal pumps, the combination of a oat chamber communicating with the suction side of a centrifugal pump, a suction pipe having a suction inlet, a suction inlet valve for the suction inlet, an air cham.- ber having a valve controlled outlet port adjacent the suction inlet, opening to the oat chamber, said air chamber having also an air vent anda valve therefor, said vent valve being'opened when the suction inlet and the valve controlled outlet port are closed, and said suction inlet, when open, communicating with said air chamber and communicating with said iloat chamber through said valve controlled outlet port, a oat in said oat chamber, and operative connections between the vent and suction inlet valves and the float,

air at atmospheric pressure is thereby admitted to the suction valve withoutvbreaking the vacuum in the suction pipe.

12. In priming apparatus for centrifugal pumps, the combination of a float chamber com-` municating with the suction side of a centrifugal pump, a suction pipe having a suction inlet, a suction inlet valve for controlling said suction inlet, a float in said float chamber connected to and operating to open and close said suction inlet valve, and an air chamber from which the suction inlet to the suction pipe opens, said air chamber opening to the float' chamber through a check valve controlled port and having a vent and a vent valve therefor operated by said float, the connections between the valves and float being constructed and arranged to simultaneously open one valve and close the other, said air chamber being adapted to supply air at atmospheric pressure to said suction inlet valve when the vent is open whereby air only may leak past a leaky valve to the closed pipe.

13. In priming apparatus for centrifugal pumps, the combination of a float chamber communicating with the suction side of a centrifugal pump, an air chamber having a vent and a valve therefor, and having a check valve controlled port opening to the float chamber, a suction pipe having a suction inlet arranged for communication with the air chamber, an air valve for controlling the passage from the air chamber to the suction inlet, and a float in said float chamber connected to the vent valve and air valve, and operating, when lowered to open the air valve and close the vent valve, whereby when the air valve isl opened, communication is established between the suction pipe, the air chamber and oat chamber, and when closed, communication is closed between the air chamber and suction pipe.

AUGUSTUS C. DURDIN, JR. 20 

